Substantial development efforts have recently focused on the synthesis of nanotubes and nanorods. These are needed for interconnecting circuits, sensors, optoelectronics and other nano-sized elements in the field that is now known as nanotechnology. These connections are needed to make ultra-compact devices.
One example of such development efforts is found in U.S. Pat. No. 6,882,051, titled “Nanowires, Nanostructures and Devices Fabricated Therefrom,” which issued to Mujamdar, et al., on Apr. 19, 2005. This patent discloses methods of fabricating and doping one-dimensional nanostructures having uniform diameters of less than approximately 200 nm.
While one-dimensional nanostructures are useful to connect two elements, branching of nanotubes and nanorods is important because it permits the interconnection of multiple elements. Substantial development efforts have produced branching for a variety of elements and methods. For one example, Dick, et al., “Synthesis of Branched ‘Nanotrees’ by Controlled Seeding of Multiple Branching Events,” Nature Materials, 3, 380 (2004), teaches methods of synthesizing branched GaP nanostructures by sequential seeding with metal nanoparticles.
To date, however, the prior art does not teach the synthesis of branched nanostructures by methods that can individually control in situ the growth process, specially for silicon- and carbon-derived nanostructures. Because of these materials' properties they are widely used in the electronics industry and in fabricating nanoscale devices. While silicon nanowires have been synthesized, there remains a need for branched and multi-branched silicon nanostructures. This invention also addresses that need.